How to send a resized image the body for a response for actix-web?

[kartikynwa]

First time working with images so I am a bit confused. This is the code that I have:

#[get("/sprite/{sprite_id}.png")]
pub async fn get_sprite(
    data: web::Data<AppState>,
    path: web::Path<(i64,)>,
) -> impl Responder {
    let (sprite_id,) = path.into_inner();

    let result = sqlx::query!("SELECT filepath FROM sprites WHERE id=?", sprite_id)
        .fetch_one(&data.db)
        .await;

    let sprite_path: PathBuf = if let Ok(row) = result {
        row.filepath.into()
    } else {
        return HttpResponse::NotFound().body("Inexistent sprite id");
    };

    let img = ImageReader::open(sprite_path)
        .unwrap()
        .decode()
        .unwrap()
        .resize(256, 256, image::imageops::FilterType::Triangle);

    HttpResponse::Ok()
        .insert_header(("content-type", "image/png"))
        .body(img.as_bytes().to_vec())
}

This compiles and runs but the response body is not a valid PNG file. I guess this because it is a decoded image and I have to encode it to a PNG before sending it but I cannot figure out how to. Any advice? Thanks.

[fintelia]

Use the write_to method:

let mut bytes: Vec<u8> = Vec::new();
img.write_to(&mut Cursor::new(&mut bytes), image::ImageOutputFormat::Png)?;